An object in equilibrium has three forces exerted on it. A 42 N force acts at 90° from the x axis and a 46 N force acts at 60°. What are the magnitude and direction of the third force?

Convert the 42N and 46N forces into x and y components. The third force will have x and y force components that balance out the sum of the other x and y components of the other two. Then use Pythagoras to find the total magnitude of the third force, and its angle will be the arctangent of its y component divided by its x component. Post back with your answer and we'll check it for you.